Pension and Other Postretirement Benefits (Details 8) (Defined benefit pension plans [Member])	12 Months Ended
Dec. 31, 2011
Defined benefit pension plans [Member]
Defined Benefit Plan Disclosure [Line Items]
The weighted-average target investment allocations in equity securities	70.00%
The weighted-average target investment allocations in fixed income securities	20.00%
The weighted-average target investment allocations in real estate	5.00%
The weighted-average target investment allocations in other investments	5.00%

Target allocation percentage of investments in debt securities to total plan assets presented on a weighted-average basis as of the measurement date of the latest statement of financial position.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph d(2)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 5

-Subparagraph (c)(i)

-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e2446-114920

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (d)(i)

-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration